flailing

AsyncDisplayKit.xcodeproj/project.pbxproj

@@ -217,6 +217,8 @@
 		509E68651B3AEDC5009B9150 /* CGRect+ASConvenience.h in Headers */ = {isa = PBXBuildFile; fileRef = 205F0E1F1B376416007741D0 /* CGRect+ASConvenience.h */; };
 		509E68661B3AEDD7009B9150 /* CGRect+ASConvenience.m in Sources */ = {isa = PBXBuildFile; fileRef = 205F0E201B376416007741D0 /* CGRect+ASConvenience.m */; };
 		6BDC61F61979037800E50D21 /* AsyncDisplayKit.h in Headers */ = {isa = PBXBuildFile; fileRef = 6BDC61F51978FEA400E50D21 /* AsyncDisplayKit.h */; settings = {ATTRIBUTES = (Public, ); }; };
+		9C49C36F1B853957000B0DD5 /* ASStackLayoutable.h in Headers */ = {isa = PBXBuildFile; fileRef = 9C49C36E1B853957000B0DD5 /* ASStackLayoutable.h */; settings = {ATTRIBUTES = (Public, ); }; };
+		9C49C3701B853961000B0DD5 /* ASStackLayoutable.h in Headers */ = {isa = PBXBuildFile; fileRef = 9C49C36E1B853957000B0DD5 /* ASStackLayoutable.h */; settings = {ATTRIBUTES = (Public, ); }; };
 		9F06E5CD1B4CAF4200F015D8 /* ASCollectionViewTests.m in Sources */ = {isa = PBXBuildFile; fileRef = 9F06E5CC1B4CAF4200F015D8 /* ASCollectionViewTests.m */; };
 		AC21EC101B3D0BF600C8B19A /* ASStackLayoutDefines.h in Headers */ = {isa = PBXBuildFile; fileRef = AC21EC0F1B3D0BF600C8B19A /* ASStackLayoutDefines.h */; settings = {ATTRIBUTES = (Public, ); }; };
 		AC3C4A511A1139C100143C57 /* ASCollectionView.h in Headers */ = {isa = PBXBuildFile; fileRef = AC3C4A4F1A1139C100143C57 /* ASCollectionView.h */; settings = {ATTRIBUTES = (Public, ); }; };
@@ -556,6 +558,7 @@
 		4640521E1A3F83C40061C0BA /* ASMultidimensionalArrayUtils.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = ASMultidimensionalArrayUtils.h; sourceTree = "<group>"; };
 		4640521F1A3F83C40061C0BA /* ASMultidimensionalArrayUtils.mm */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.objcpp; path = ASMultidimensionalArrayUtils.mm; sourceTree = "<group>"; };
 		6BDC61F51978FEA400E50D21 /* AsyncDisplayKit.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = AsyncDisplayKit.h; sourceTree = "<group>"; };
+		9C49C36E1B853957000B0DD5 /* ASStackLayoutable.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; name = ASStackLayoutable.h; path = AsyncDisplayKit/Layout/ASStackLayoutable.h; sourceTree = "<group>"; };
 		9F06E5CC1B4CAF4200F015D8 /* ASCollectionViewTests.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = ASCollectionViewTests.m; sourceTree = "<group>"; };
 		AC21EC0F1B3D0BF600C8B19A /* ASStackLayoutDefines.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; name = ASStackLayoutDefines.h; path = AsyncDisplayKit/Layout/ASStackLayoutDefines.h; sourceTree = "<group>"; };
 		AC3C4A4F1A1139C100143C57 /* ASCollectionView.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = ASCollectionView.h; sourceTree = "<group>"; };
@@ -958,6 +961,7 @@
 				ACF6ED131B17843500DA7C62 /* ASOverlayLayoutSpec.mm */,
 				ACF6ED141B17843500DA7C62 /* ASRatioLayoutSpec.h */,
 				ACF6ED151B17843500DA7C62 /* ASRatioLayoutSpec.mm */,
+				9C49C36E1B853957000B0DD5 /* ASStackLayoutable.h */,
 				AC21EC0F1B3D0BF600C8B19A /* ASStackLayoutDefines.h */,
 				ACF6ED161B17843500DA7C62 /* ASStackLayoutSpec.h */,
 				ACF6ED171B17843500DA7C62 /* ASStackLayoutSpec.mm */,
@@ -1004,6 +1008,7 @@
 			files = (
 				AC21EC101B3D0BF600C8B19A /* ASStackLayoutDefines.h in Headers */,
 				AC47D9451B3BB41900AAEE9D /* ASRelativeSize.h in Headers */,
+				9C49C36F1B853957000B0DD5 /* ASStackLayoutable.h in Headers */,
 				ACF6ED511B17847A00DA7C62 /* ASStackUnpositionedLayout.h in Headers */,
 				ACF6ED2D1B17843500DA7C62 /* ASRatioLayoutSpec.h in Headers */,
 				ACF6ED261B17843500DA7C62 /* ASLayoutSpec.h in Headers */,
@@ -1170,6 +1175,7 @@
 				B350620C1B010EFD0018CF92 /* ASTableViewProtocols.h in Headers */,
 				B35062481B010EFD0018CF92 /* _AS-objc-internal.h in Headers */,
 				B350623F1B010EFD0018CF92 /* _ASAsyncTransactionContainer.h in Headers */,
+				9C49C3701B853961000B0DD5 /* ASStackLayoutable.h in Headers */,
 				34EFC7731B701D0700AD841F /* ASStaticLayoutSpec.h in Headers */,
 				B35062081B010EFD0018CF92 /* ASScrollNode.h in Headers */,
 				B35061F51B010EFD0018CF92 /* ASCollectionView.h in Headers */,

AsyncDisplayKit/ASDisplayNode.h

@@ -13,7 +13,7 @@
 #import <AsyncDisplayKit/ASDealloc2MainObject.h>
 #import <AsyncDisplayKit/ASDimension.h>
 
-#import <AsyncDisplayKit/ASLayoutable.h>
+#import <AsyncDisplayKit/ASStackLayoutable.h>
 
 /**
  * UIView creation block. Used to create the backing view of a new display node.
@@ -40,7 +40,7 @@ typedef CALayer *(^ASDisplayNodeLayerBlock)();
  *
  */
 
-@interface ASDisplayNode : ASDealloc2MainObject <ASLayoutable>
+@interface ASDisplayNode : ASDealloc2MainObject <ASStackLayoutable>
 
 
 /** @name Initializing a node object */

AsyncDisplayKit/ASDisplayNode.mm

@@ -48,8 +48,6 @@
 @synthesize flexBasis = _flexBasis;
 @synthesize alignSelf = _alignSelf;
 @synthesize preferredFrameSize = _preferredFrameSize;
-@synthesize ascender = _ascender;
-@synthesize descender = _descender;
 
 BOOL ASDisplayNodeSubclassOverridesSelector(Class subclass, SEL selector)
 {
@@ -159,8 +157,6 @@ void ASDisplayNodeRespectThreadAffinityOfNode(ASDisplayNode *node, void (^block)
 
   _flexBasis = ASRelativeDimensionUnconstrained;
   _preferredFrameSize = CGSizeZero;
-  _ascender = 0;
-  _descender = 0;
 }
 
 - (id)init
@@ -457,6 +453,11 @@ void ASDisplayNodeRespectThreadAffinityOfNode(ASDisplayNode *node, void (^block)
 
 #pragma mark -
 
+- (CGFloat)distanceToBaseline:(ASStackLayoutAlignItems)baselineAlignmentType
+{
+  return 0;
+}
+
 - (CGSize)measure:(CGSize)constrainedSize
 {
   return [self measureWithSizeRange:ASSizeRangeMake(CGSizeZero, constrainedSize)].size;

AsyncDisplayKit/ASTextNode.mm

@@ -17,6 +17,7 @@
 #import <AsyncDisplayKit/ASTextNodeTextKitHelpers.h>
 #import <AsyncDisplayKit/ASDisplayNodeExtras.h>
 
+#import "ASInternalHelpers.h"
 #import "ASTextNodeRenderer.h"
 #import "ASTextNodeShadower.h"
 
@@ -105,6 +106,9 @@ ASDISPLAYNODE_INLINE CGFloat ceilPixelValue(CGFloat f)
   ASTextNodeShadower *_shadower;
 
   UILongPressGestureRecognizer *_longPressGestureRecognizer;
+  
+  CGFloat _topBaseline;
+  CGFloat _bottomBaseline;
 }
 
 #pragma mark - NSObject
@@ -356,8 +360,24 @@ ASDISPLAYNODE_INLINE CGFloat ceilPixelValue(CGFloat f)
     }
   });
   
-  self.ascender = round([[attributedString attribute:NSFontAttributeName atIndex:0 effectiveRange:NULL] ascender] * [UIScreen mainScreen].scale)/[UIScreen mainScreen].scale;
+  _topBaseline = round([[attributedString attribute:NSFontAttributeName atIndex:0 effectiveRange:NULL] ascender] * ASScreenScale())/ASScreenScale();
-  self.descender = round([[attributedString attribute:NSFontAttributeName atIndex:attributedString.length - 1 effectiveRange:NULL] descender] * [UIScreen mainScreen].scale)/[UIScreen mainScreen].scale;
+  _bottomBaseline = round([[attributedString attribute:NSFontAttributeName atIndex:attributedString.length - 1 effectiveRange:NULL] descender] * ASScreenScale())/ASScreenScale();
+}
+
+#pragma mark - Baseline computation
+
+- (CGFloat)distanceToBaseline:(ASStackLayoutAlignItems)baselineAlignmentType
+{
+  switch (baselineAlignmentType) {
+    case ASStackLayoutAlignItemsLastBaseline:
+      return self.calculatedSize.height + _bottomBaseline;
+      
+    case ASStackLayoutAlignItemsFirstBaseline:
+      return _topBaseline;
+      
+    default:
+      return 0;
+  }
 }
 
 #pragma mark - Text Layout

AsyncDisplayKit/Layout/ASLayoutSpec.h

@@ -8,9 +8,9 @@
  *
  */
 
-#import <AsyncDisplayKit/ASLayoutable.h>
+#import <AsyncDisplayKit/ASStackLayoutable.h>
 
 /** A layout spec is an immutable object that describes a layout, loosely inspired by React. */
-@interface ASLayoutSpec : NSObject <ASLayoutable>
+@interface ASLayoutSpec : NSObject <ASStackLayoutable>
 
 @end

AsyncDisplayKit/Layout/ASLayoutSpec.mm

@@ -24,8 +24,6 @@
 @synthesize flexShrink = _flexShrink;
 @synthesize flexBasis = _flexBasis;
 @synthesize alignSelf = _alignSelf;
-@synthesize ascender = _ascender;
-@synthesize descender = _descender;
 
 + (instancetype)new
 {
@@ -36,6 +34,11 @@
   return spec;
 }
 
+- (CGFloat)distanceToBaseline:(ASStackLayoutAlignItems)baselineAlignmentType
+{
+    return 0;
+}
+
 #pragma mark - Layout
 
 - (ASLayout *)measureWithSizeRange:(ASSizeRange)constrainedSize

AsyncDisplayKit/Layout/ASLayoutable.h

@@ -20,53 +20,6 @@
  */
 @protocol ASLayoutable <NSObject>
 
-/** 
- * @abstract Additional space to place before this object in the stacking direction.
- * Used when attached to a stack layout.
- */
-@property (nonatomic, readwrite) CGFloat spacingBefore;
-
-/**
- * @abstract Additional space to place after this object in the stacking direction.
- * Used when attached to a stack layout.
- */
-@property (nonatomic, readwrite) CGFloat spacingAfter;
-
-/**
- * @abstract If the sum of childrens' stack dimensions is less than the minimum size, should this object grow?
- * Used when attached to a stack layout.
- */
-@property (nonatomic, readwrite) BOOL flexGrow;
-
-/**
- * @abstract If the sum of childrens' stack dimensions is greater than the maximum size, should this object shrink?
- * Used when attached to a stack layout.
- */
-@property (nonatomic, readwrite) BOOL flexShrink;
-
-/**
- * @abstract Specifies the initial size in the stack dimension for this object.
- * Default to ASRelativeDimensionUnconstrained.
- * Used when attached to a stack layout.
- */
-@property (nonatomic, readwrite) ASRelativeDimension flexBasis;
-
-/**
- * @abstract Orientation of the object along cross axis, overriding alignItems
- * Used when attached to a stack layout.
- */
-@property (nonatomic, readwrite) ASStackLayoutAlignSelf alignSelf;
-
-/**
- *  @abstract Used for baseline alignment. The distance from the top of the object to its baseline.
- */
-@property (nonatomic, readwrite) CGFloat ascender;
-
-/**
- *  @abstract Used for baseline alignment. The distance from the baseline of the object to its bottom.
- */
-@property (nonatomic, readwrite) CGFloat descender;
-
 /**
  * @abstract Calculate a layout based on given size range.
  *

AsyncDisplayKit/Layout/ASStackLayoutDefines.h

@@ -8,6 +8,49 @@
  *
  */
 
+/** The direction children are stacked in */
+typedef NS_ENUM(NSUInteger, ASStackLayoutDirection) {
+  /** Children are stacked vertically */
+  ASStackLayoutDirectionVertical,
+  /** Children are stacked horizontally */
+  ASStackLayoutDirectionHorizontal,
+};
+
+/** If no children are flexible, how should this spec justify its children in the available space? */
+typedef NS_ENUM(NSUInteger, ASStackLayoutJustifyContent) {
+  /**
+   On overflow, children overflow out of this spec's bounds on the right/bottom side.
+   On underflow, children are left/top-aligned within this spec's bounds.
+   */
+  ASStackLayoutJustifyContentStart,
+  /**
+   On overflow, children are centered and overflow on both sides.
+   On underflow, children are centered within this spec's bounds in the stacking direction.
+   */
+  ASStackLayoutJustifyContentCenter,
+  /**
+   On overflow, children overflow out of this spec's bounds on the left/top side.
+   On underflow, children are right/bottom-aligned within this spec's bounds.
+   */
+  ASStackLayoutJustifyContentEnd,
+};
+
+/** Orientation of children along cross axis */
+typedef NS_ENUM(NSUInteger, ASStackLayoutAlignItems) {
+  /** Align children to start of cross axis */
+  ASStackLayoutAlignItemsStart,
+  /** Align children with end of cross axis */
+  ASStackLayoutAlignItemsEnd,
+  /** Center children on cross axis */
+  ASStackLayoutAlignItemsCenter,
+  /** Expand children to fill cross axis */
+  ASStackLayoutAlignItemsStretch,
+  /** Children align along the first baseline of the stack. Only available for horizontal stack nodes */
+  ASStackLayoutAlignItemsFirstBaseline,
+    /** Children align along the last baseline of the stack. Only available for horizontal stack nodes */
+  ASStackLayoutAlignItemsLastBaseline,
+};
+
 /**
  Each child may override their parent stack's cross axis alignment.
  @see ASStackLayoutAlignItems
@@ -23,8 +66,6 @@ typedef NS_ENUM(NSUInteger, ASStackLayoutAlignSelf) {
   ASStackLayoutAlignSelfCenter,
   /** Expand to fill cross axis */
   ASStackLayoutAlignSelfStretch,
-  /** Children align to their first baseline. Only available for horizontal stack nodes */
+    
-  ASStackLayoutAlignSelfBaselineFirst,
+  /** Note: All children in a stack must have the same baseline align type */
-  /** Children align to their last baseline. Only available for horizontal stack nodes */
-  ASStackLayoutAlignSelfBaselineLast,
 };

AsyncDisplayKit/Layout/ASStackLayoutSpec.h

@@ -9,49 +9,7 @@
  */
 
 #import <AsyncDisplayKit/ASLayoutSpec.h>
-
+#import <AsyncDisplayKit/ASStackLayoutDefines.h>
-/** The direction children are stacked in */
-typedef NS_ENUM(NSUInteger, ASStackLayoutDirection) {
-  /** Children are stacked vertically */
-  ASStackLayoutDirectionVertical,
-  /** Children are stacked horizontally */
-  ASStackLayoutDirectionHorizontal,
-};
-
-/** If no children are flexible, how should this spec justify its children in the available space? */
-typedef NS_ENUM(NSUInteger, ASStackLayoutJustifyContent) {
-  /**
-   On overflow, children overflow out of this spec's bounds on the right/bottom side.
-   On underflow, children are left/top-aligned within this spec's bounds.
-   */
-  ASStackLayoutJustifyContentStart,
-  /**
-   On overflow, children are centered and overflow on both sides.
-   On underflow, children are centered within this spec's bounds in the stacking direction.
-   */
-  ASStackLayoutJustifyContentCenter,
-  /**
-   On overflow, children overflow out of this spec's bounds on the left/top side.
-   On underflow, children are right/bottom-aligned within this spec's bounds.
-   */
-  ASStackLayoutJustifyContentEnd,
-};
-
-/** Orientation of children along cross axis */
-typedef NS_ENUM(NSUInteger, ASStackLayoutAlignItems) {
-  /** Align children to start of cross axis */
-  ASStackLayoutAlignItemsStart,
-  /** Align children with end of cross axis */
-  ASStackLayoutAlignItemsEnd,
-  /** Center children on cross axis */
-  ASStackLayoutAlignItemsCenter,
-  /** Expand children to fill cross axis */
-  ASStackLayoutAlignItemsStretch,
-  /** Children align to their first baseline. Only available for horizontal stack nodes */
-  ASStackLayoutAlignItemsBaselineFirst,
-  /** Children align to their last baseline. Only available for horizontal stack nodes */
-  ASStackLayoutAlignItemsBaselineLast,
-};
 
 typedef struct {
   /** Specifies the direction children are stacked in. */

AsyncDisplayKit/Layout/ASStackLayoutSpec.mm

@@ -25,8 +25,9 @@
 @implementation ASStackLayoutSpec
 {
   ASStackLayoutSpecStyle _style;
-  std::vector<id<ASLayoutable>> _children;
+  std::vector<id<ASStackLayoutable>> _children;
   ASDN::RecursiveMutex _propertyLock;
+  CGFloat _distanceToBaseline;
 }
 
 + (instancetype)newWithStyle:(ASStackLayoutSpecStyle)style children:(NSArray *)children
@@ -34,8 +35,10 @@
   ASStackLayoutSpec *spec = [super new];
   if (spec) {
     spec->_style = style;
-    spec->_children = std::vector<id<ASLayoutable>>();
+    spec->_children = std::vector<id<ASStackLayoutable>>();
-    for (id<ASLayoutable> child in children) {
+    for (id<ASStackLayoutable> child in children) {
+      ASDisplayNodeAssert([child conformsToProtocol:@protocol(ASStackLayoutable)], @"child must conform to ASStackLayoutable");
+
       spec->_children.push_back(child);
     }
   }
@@ -55,12 +58,16 @@
   NSArray *sublayouts = [NSArray arrayWithObjects:&positionedLayout.sublayouts[0] count:positionedLayout.sublayouts.size()];
   
   ASDN::MutexLocker l(_propertyLock);
-  self.ascender = positionedLayout.ascender;
+  _distanceToBaseline = positionedLayout.distanceToBaseline;
-  self.descender = positionedLayout.descender;
   
   return [ASLayout newWithLayoutableObject:self
                                       size:ASSizeRangeClamp(constrainedSize, finalSize)
                                 sublayouts:sublayouts];
 }
 
+- (CGFloat)distanceToBaseline:(ASStackLayoutAlignItems)baselineAlignmentType
+{
+  return _distanceToBaseline;
+}
+
 @end

AsyncDisplayKit/Layout/ASStackLayoutable.h

@@ -0,0 +1,57 @@
+/*
+ *  Copyright (c) 2014-present, Facebook, Inc.
+ *  All rights reserved.
+ *
+ *  This source code is licensed under the BSD-style license found in the
+ *  LICENSE file in the root directory of this source tree. An additional grant
+ *  of patent rights can be found in the PATENTS file in the same directory.
+ *
+ */
+
+#import <AsyncDisplayKit/ASLayoutable.h>
+
+@protocol ASStackLayoutable <ASLayoutable>
+
+/**
+ * @abstract Additional space to place before this object in the stacking direction.
+ * Used when attached to a stack layout.
+ */
+@property (nonatomic, readwrite) CGFloat spacingBefore;
+
+/**
+ * @abstract Additional space to place after this object in the stacking direction.
+ * Used when attached to a stack layout.
+ */
+@property (nonatomic, readwrite) CGFloat spacingAfter;
+
+/**
+ * @abstract If the sum of childrens' stack dimensions is less than the minimum size, should this object grow?
+ * Used when attached to a stack layout.
+ */
+@property (nonatomic, readwrite) BOOL flexGrow;
+
+/**
+ * @abstract If the sum of childrens' stack dimensions is greater than the maximum size, should this object shrink?
+ * Used when attached to a stack layout.
+ */
+@property (nonatomic, readwrite) BOOL flexShrink;
+
+/**
+ * @abstract Specifies the initial size in the stack dimension for this object.
+ * Default to ASRelativeDimensionUnconstrained.
+ * Used when attached to a stack layout.
+ */
+@property (nonatomic, readwrite) ASRelativeDimension flexBasis;
+
+/**
+ * @abstract Orientation of the object along cross axis, overriding alignItems
+ * Used when attached to a stack layout.
+ */
+@property (nonatomic, readwrite) ASStackLayoutAlignSelf alignSelf;
+
+/**
+ *  @abstract Used for baseline alignment in stack spec. The distance from the top of the object to its baseline.
+ */
+- (CGFloat)distanceToBaseline:(ASStackLayoutAlignItems)baselineAlignmentType;
+
+@end

AsyncDisplayKit/Private/ASStackLayoutSpecUtilities.h

@@ -55,10 +55,6 @@ inline ASStackLayoutAlignItems alignment(ASStackLayoutAlignSelf childAlignment,
       return ASStackLayoutAlignItemsStart;
     case ASStackLayoutAlignSelfStretch:
       return ASStackLayoutAlignItemsStretch;
-    case ASStackLayoutAlignSelfBaselineFirst:
-      return ASStackLayoutAlignItemsBaselineFirst;
-    case ASStackLayoutAlignSelfBaselineLast:
-      return ASStackLayoutAlignItemsBaselineLast;
     case ASStackLayoutAlignSelfAuto:
     default:
       return stackAlignment;

AsyncDisplayKit/Private/ASStackPositionedLayout.h

@@ -17,8 +17,7 @@
 struct ASStackPositionedLayout {
   const std::vector<ASLayout *> sublayouts;
   const CGFloat crossSize;
-  const CGFloat ascender;
+  const CGFloat distanceToBaseline;
-  const CGFloat descender;
 
   /** Given an unpositioned layout, computes the positions each child should be placed at. */
   static ASStackPositionedLayout compute(const ASStackUnpositionedLayout &unpositionedLayout,

AsyncDisplayKit/Private/ASStackPositionedLayout.mm

@@ -18,10 +18,8 @@
 static CGFloat baselineForItem(const ASStackLayoutSpecStyle &style,
                                const ASStackUnpositionedItem &item) {
   const ASStackLayoutAlignItems alignItems = alignment(item.child.alignSelf, style.alignItems);
-  if (alignItems == ASStackLayoutAlignItemsBaselineFirst) {
+  if (alignItems == ASStackLayoutAlignItemsFirstBaseline || alignItems == ASStackLayoutAlignItemsLastBaseline) {
-    return item.child.ascender;
+    return [item.child distanceToBaseline:alignItems];
-  } else if (alignItems == ASStackLayoutAlignItemsBaselineLast) {
-    return  item.layout.size.height + item.child.descender;
   }
   return 0;
 }
@@ -39,9 +37,8 @@ static CGFloat crossOffset(const ASStackLayoutSpecStyle &style,
     case ASStackLayoutAlignItemsStart:
     case ASStackLayoutAlignItemsStretch:
       return 0;
-    case ASStackLayoutAlignItemsBaselineFirst:
+    case ASStackLayoutAlignItemsLastBaseline:
-      return maxBaseline - l.child.ascender;
+    case ASStackLayoutAlignItemsFirstBaseline:
-    case ASStackLayoutAlignItemsBaselineLast:
       return maxBaseline - baselineForItem(style, l);
   }
 }
@@ -78,11 +75,11 @@ static ASStackPositionedLayout stackedLayout(const ASStackLayoutSpecStyle &style
     first = NO;
     l.layout.position = p + directionPoint(style.direction, 0, crossOffset(style, l, crossSize, maxBaseline));
     
-    CGFloat spacingAfterBaseline = (style.direction == ASStackLayoutDirectionVertical && style.baselineRelativeArrangement) ? l.child.descender : 0;
+    CGFloat spacingAfterBaseline = (style.direction == ASStackLayoutDirectionVertical && style.baselineRelativeArrangement) ? l.layout.size.height - [l.child distanceToBaseline:style.alignItems] : 0;
     p = p + directionPoint(style.direction, stackDimension(style.direction, l.layout.size) + l.child.spacingAfter + spacingAfterBaseline, 0);
     return l.layout;
   });
-  return {stackedChildren, crossSize, maxBaseline, maxBaseline == 0 ? 0 : maxBaseline - crossSize};
+  return {stackedChildren, crossSize, maxBaseline};
 }
 
 ASStackPositionedLayout ASStackPositionedLayout::compute(const ASStackUnpositionedLayout &unpositionedLayout,

AsyncDisplayKit/Private/ASStackUnpositionedLayout.h

@@ -15,7 +15,7 @@
 
 struct ASStackUnpositionedItem {
   /** The original source child. */
-  id<ASLayoutable> child;
+  id<ASStackLayoutable> child;
   /** The proposed layout. */
   ASLayout *layout;
 };
@@ -30,7 +30,7 @@ struct ASStackUnpositionedLayout {
   const CGFloat violation;
 
   /** Given a set of children, computes the unpositioned layouts for those children. */
-  static ASStackUnpositionedLayout compute(const std::vector<id<ASLayoutable>> &children,
+  static ASStackUnpositionedLayout compute(const std::vector<id<ASStackLayoutable>> &children,
                                            const ASStackLayoutSpecStyle &style,
                                            const ASSizeRange &sizeRange);
 };

AsyncDisplayKit/Private/ASStackUnpositionedLayout.mm

@@ -18,7 +18,7 @@
 /**
  Sizes the child given the parameters specified, and returns the computed layout.
  */
-static ASLayout *crossChildLayout(const id<ASLayoutable> child,
+static ASLayout *crossChildLayout(const id<ASStackLayoutable> child,
                                   const ASStackLayoutSpecStyle style,
                                   const CGFloat stackMin,
                                   const CGFloat stackMax,
@@ -186,7 +186,7 @@ static std::function<BOOL(const ASStackUnpositionedItem &)> isFlexibleInViolatio
   }
 }
 
-ASDISPLAYNODE_INLINE BOOL isFlexibleInBothDirections(id<ASLayoutable> child)
+ASDISPLAYNODE_INLINE BOOL isFlexibleInBothDirections(id<ASStackLayoutable> child)
 {
   return child.flexGrow && child.flexShrink;
 }
@@ -195,7 +195,7 @@ ASDISPLAYNODE_INLINE BOOL isFlexibleInBothDirections(id<ASLayoutable> child)
  If we have a single flexible (both shrinkable and growable) child, and our allowed size range is set to a specific
  number then we may avoid the first "intrinsic" size calculation.
  */
-ASDISPLAYNODE_INLINE BOOL useOptimizedFlexing(const std::vector<id<ASLayoutable>> &children,
+ASDISPLAYNODE_INLINE BOOL useOptimizedFlexing(const std::vector<id<ASStackLayoutable>> &children,
                                               const ASStackLayoutSpecStyle &style,
                                               const ASSizeRange &sizeRange)
 {
@@ -283,7 +283,7 @@ static void flexChildrenAlongStackDimension(std::vector<ASStackUnpositionedItem>
  Performs the first unconstrained layout of the children, generating the unpositioned items that are then flexed and
  stretched.
  */
-static std::vector<ASStackUnpositionedItem> layoutChildrenAlongUnconstrainedStackDimension(const std::vector<id<ASLayoutable>> &children,
+static std::vector<ASStackUnpositionedItem> layoutChildrenAlongUnconstrainedStackDimension(const std::vector<id<ASStackLayoutable>> &children,
                                                                                            const ASStackLayoutSpecStyle &style,
                                                                                            const ASSizeRange &sizeRange,
                                                                                            const CGSize size,
@@ -292,7 +292,7 @@ static std::vector<ASStackUnpositionedItem> layoutChildrenAlongUnconstrainedStac
   const CGFloat minCrossDimension = crossDimension(style.direction, sizeRange.min);
   const CGFloat maxCrossDimension = crossDimension(style.direction, sizeRange.max);
   
-  return AS::map(children, [&](id<ASLayoutable> child) -> ASStackUnpositionedItem {
+  return AS::map(children, [&](id<ASStackLayoutable> child) -> ASStackUnpositionedItem {
     const BOOL isUnconstrainedFlexBasis = ASRelativeDimensionEqualToRelativeDimension(ASRelativeDimensionUnconstrained, child.flexBasis);
     const CGFloat exactStackDimension = ASRelativeDimensionResolve(child.flexBasis, stackDimension(style.direction, size));
 
@@ -312,7 +312,7 @@ static std::vector<ASStackUnpositionedItem> layoutChildrenAlongUnconstrainedStac
   });
 }
 
-ASStackUnpositionedLayout ASStackUnpositionedLayout::compute(const std::vector<id<ASLayoutable>> &children,
+ASStackUnpositionedLayout ASStackUnpositionedLayout::compute(const std::vector<id<ASStackLayoutable>> &children,
                                                              const ASStackLayoutSpecStyle &style,
                                                              const ASSizeRange &sizeRange)
 {